Plug in Hybrid electric Cars Emit Almost as Heavily as Gasoline Vehicles, Study Finds

PHEVs produce nearly 5x more global warming emissions than lab-reported figures indicate, as per a new report.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a advocacy organization. That contrasts significantly with lab tests, which suggested a 75% decrease in emissions.

Researchers studied data from in-vehicle energy use monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while official emissions are falling,” said a lead researcher participating in the report. “That gap is growing and creates a significant problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Key Factors Behind the Emissions Gap

Researchers attributed most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery mode compared to overall distance. They found that just a quarter of travel was done in EV mode, while lab estimates assumed over four-fifths.

Even, when running in EV mode, emission levels were significantly higher than official projections. That happened because electric motors were not strong sufficient to function alone, leading to engines burning gasoline for almost a third of the distance covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the underestimation of PHEV emissions enabled four major automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 extra per year in running expenses than would be estimated under laboratory tests.

“The strong claims that manufacturers like to make about their PHEV cars are obviously way off the truth,” commented a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the planet and cutting money. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ production, and operating costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been brought back into policy discussions as automakers have pressed the EU to weaken CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and resistance from member states with large car industries.

Several senior politicians have suggested PHEVs as a possible “compromise” solution to include in the legislation.

An independent energy economics expert, who was unaffiliated with the study, called the analysis a “highly valuable addition” after years in which segments of the automotive sector argued there was too little information to accurately evaluate actual emissions.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional cars,” they stated. “All regulatory changes concerning PHEVs should be made with extreme caution and in the light of this data.”